Origin

Early 19th century (in the sense 'drink together'): from archaic hob or nob, hob and nob, probably meaning 'give and take', used by two people drinking to each other's health, from dialect hab nab 'have or not have'.

In the 18th century drinkers would toast each other alternately with the words ‘hob or nob’ or ‘hob and nob’, probably meaning ‘give or take’ or ‘have or have not’. Toasting each other in this way was ‘to drink hob or nob’, or, from the early 19th century, simply to hobnob. The image of convivial companionship led to the sense ‘to be on familiar terms, to talk informally’, which during the 20th century acquired negative associations of mixing socially with those felt to be of higher social status. It was the convivial connotations that probably persuaded McVitie's to come up with the name HobNobs for their new biscuit in 1985.